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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IDR Working Group R. Raszuk, Ed. 3 Internet-Draft Mirantis Inc. 4 Intended status: Standards Track J. Haas 5 Expires: December 27, 2015 Juniper Networks 6 June 25, 2015 8 Registered Wide BGP Community Values 9 draft-ietf-idr-registered-wide-bgp-communities-00 11 Abstract 13 Communicating various routing policies via route tagging plays an 14 important role in external BGP peering relations. The most common 15 tool used today to attach various information about routes is 16 realized with the use of BGP communities. Such information is 17 important for the peering AS to perform some mutually agreed actions 18 without the need to maintain a separate offline database for each 19 pair of prefix and an associated with it requested set of action 20 entries. 22 This document proposes to establish a new IANA maintained registry of 23 most commonly used Wide BGP Communities by network operators. Such 24 public registry will allow for easy refernece and clear 25 interpretation of the actions associated with received community 26 values. 28 Status of This Memo 30 This Internet-Draft is submitted in full conformance with the 31 provisions of BCP 78 and BCP 79. 33 Internet-Drafts are working documents of the Internet Engineering 34 Task Force (IETF). Note that other groups may also distribute 35 working documents as Internet-Drafts. The list of current Internet- 36 Drafts is at http://datatracker.ietf.org/drafts/current/. 38 Internet-Drafts are draft documents valid for a maximum of six months 39 and may be updated, replaced, or obsoleted by other documents at any 40 time. It is inappropriate to use Internet-Drafts as reference 41 material or to cite them other than as "work in progress." 43 This Internet-Draft will expire on December 27, 2015. 45 Copyright Notice 47 Copyright (c) 2015 IETF Trust and the persons identified as the 48 document authors. All rights reserved. 50 This document is subject to BCP 78 and the IETF Trust's Legal 51 Provisions Relating to IETF Documents 52 (http://trustee.ietf.org/license-info) in effect on the date of 53 publication of this document. Please review these documents 54 carefully, as they describe your rights and restrictions with respect 55 to this document. Code Components extracted from this document must 56 include Simplified BSD License text as described in Section 4.e of 57 the Trust Legal Provisions and are provided without warranty as 58 described in the Simplified BSD License. 60 Table of Contents 62 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 63 2. Globally significant pre-defined values . . . . . . . . . . . 3 64 2.1. Well Known Standard BGP Communities . . . . . . . . . . . 3 65 2.2. Registered pre-defined Wide BGP Communities . . . . . . . 3 66 2.2.1. General Registered Wide BGP Community Values . . . . 4 67 2.2.2. Advertisement control Registered Wide BGP Communities 7 68 2.2.3. AS source marking Registered Wide BGP Communities . . 8 69 2.2.4. Return path influencing Registered Wide BGP 70 Communities . . . . . . . . . . . . . . . . . . . . . 10 71 2.2.5. AS_PATH modifying Registered Wide BGP Communities . . 10 72 2.2.6. Local Preference Registered Community . . . . . . . . 11 73 2.2.7. AS_PATH TTL Registered Community . . . . . . . . . . 12 74 2.2.8. GEO-LOCATION Registered Community . . . . . . . . . . 12 75 3. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 76 4. ECMP Hint Registered Community . . . . . . . . . . . . . . . 14 77 5. Security considerations . . . . . . . . . . . . . . . . . . . 14 78 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 79 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 16 80 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 17 81 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 17 82 9.1. Normative References . . . . . . . . . . . . . . . . . . 17 83 9.2. Informative References . . . . . . . . . . . . . . . . . 17 84 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17 86 1. Introduction 88 RFC 1997 [RFC1997] defines a BGP Community Attribute to be used as a 89 tool to contain in BGP update message various additional information 90 about routes which may help to automate peering administration. As 91 defined in RFC 1997 [RFC1997] BGP Communities attribute consists of 92 one or more sets of four octet values, where each one of them 93 specifies a different community. Except two reserved ranges the 94 encoding of community values mandates that first two octets are to 95 contain the Autonomous System number followed by next two octets 96 containing locally defined value. 98 This document lists the most commonly used today BGP communities as 99 well as provides a new registry for future definitions. 101 2. Globally significant pre-defined values 103 2.1. Well Known Standard BGP Communities 105 According to RFC 1997 as well as to IANA's Well-Known BGP Communities 106 registry today the following BGP communities are defined to have 107 global significance: 109 +------------+---------------------+----------------------------+ 110 | 0xFFFF0000 | planned-shut | [draft-francois-bgp-gshut] | 111 | 0xFFFFFF01 | NO_EXPORT | [RFC1997] | 112 | 0xFFFFFF02 | NO_ADVERTISE | [RFC1997] | 113 | 0xFFFFFF03 | NO_EXPORT_SUBCONFED | [RFC1997] | 114 | 0xFFFFFF04 | NOPEER | [RFC3765] | 115 +------------+---------------------+----------------------------+ 117 This document recommends for simplicity as well as for avoidance of 118 backward compatibility issues the continued use of BGP Standard 119 Community Attribute type 8 as defined in RFC 1997 to distribute non 120 Autonomous System specific Well-Known BGP Communities. 122 For the same reason the described registry does not intend to 123 obsolete BGP Extended Community Attribute and any already defined and 124 deployed extended communities. The new registry is to be used 125 primarly for new community definitions in particular those which 126 require to carry various new parameters or which should be propagated 127 with a controled scope and radius. 129 2.2. Registered pre-defined Wide BGP Communities 131 It has been requested numerous times to have a globally unified way 132 to express some particular Autonomous System based routing policies. 133 When defining a new way to encode bgp communities we have an 134 opportunity to define set of new registered routing policies and 135 route markings which could be passed within and between Autonomous 136 Systems resulting in their common interpretation. 138 This document will request IANA to define and maintain a new registry 139 for pre-defined Wide BGP Community values. The allocation policy is 140 on a first come first served basis. 142 It is recommended that an implementation supports by an explicit 143 enabling defined below Registered Wide BGP Communities. Depending on 144 the BGP implementation support it is recommended that an 145 implementation would support Registered Wide BGP Communities without 146 breaking static or dynamic peer/update groups. However it needs to 147 be pointed out that support of all Registered Wide BGP Communities is 148 not mandatory. It will be perfectly valid for any BGP implementation 149 to support only subset of Wide BGP Communities. 151 It is strongly advised that each Autonomous System does an inbound 152 verification of received Wide BGP Communities from all of its EBGP 153 peers before accepting them and propagating within their own domain. 155 The document does not mandate nor enforces that given registered type 156 value of Wide BGP Community would be of transitive or non-transitive 157 type. It is for the operator to determine the propagation AS radius 158 required for such community when appending it to routing information. 159 However the document will provide a transitivity radius 160 recommendation to defined communities. 162 The following Wide BGP Communities have global significance and their 163 execution should be uniformly implemented by any BGP speaker 164 supporting given set of Wide BGP Communities. 166 The defined below value of the community should be interpreted as 167 registered value only if "R" - registered bit is set in the community 168 Type 1 container as described in [draft-raszuk-wide-bgp-communities] 169 Otherwise the value is local and it's actions is locally defined by 170 the operator. 172 2.2.1. General Registered Wide BGP Community Values 174 The below set of communities will be defined to be carried in Wide 175 BGP Community Type 1, with the container type values (Community 176 Registered Value) as per Section 6. 178 0 1 2 3 179 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 180 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 181 | 0x0001 |R C 0 0 0 0 0 0| Hop Count | 182 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 183 | Length | 184 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 185 | Registered Community Value | 186 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 187 | Source AS Number | 188 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 189 | Context AS Number | 190 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 191 | Wide Community Target(s) TLV (optional) | 192 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 193 | Wide Community Exclude Target(s) TLV (optional) | 194 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 195 | Wide Community Parameter(s) TLV (optional) | 196 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 198 Figure 1: Wide BGP Community Type 1 200 Description format: 202 TYPE: 203 0x0001 (constant for this registry) 204 FLAGS "F": 205 R - Registered bit (Set to 1 for registered values) 206 C - Confederation bit (Set when applicable) 207 HOP COUNT "H": 208 Defines domain or sub-domain propagation radius 209 LENGTH "L": 210 Length of the Container Type 1 in octets 211 REGISTERED COMMUNITY VALUE "R": 212 Value of the community in registry 213 SOURCE AS "S": 214 Originator AS of Wide BGP Community 215 CONTEXT AS "C": 216 For registered communities carries predefined meaning 217 or otherwise should be set to 0x00000000 218 TARGET TLV "T": 219 Set of atoms containing targets for execution 220 EXCLUDE TARGET TLV "E": 221 Set of atoms containing excluded targets for execution 222 PARAMETER TLV "P": 223 Set of atoms containing optional parameters for execution 225 BLACKHOLE 226 Type: 0x0001 S = src AS # 227 F = 0x80 C = 0x00000000 228 H = Operator's defined T = none 229 L = 18 octets E = none 230 R = IANA assigned P = none 232 DESCRIPTION - All transit traffic to destinations for which 233 advertised routes carry such community value should be dropped. It 234 is recommended that specified Autonomous System number should be 235 eligible and verified by BGP Origin Validation functionality to 236 advertise given BGP destinations. 238 SOURCE FILTER 239 Type: 0x0001 S = src AS # 240 F = 0x80 C = 0x00000000 241 H = Operator's defined T = none 242 L = 18 octets E = none 243 R = IANA assigned P = none 245 DESCRIPTION - All transit traffic which source addresses have been 246 tagged by such Wide BGP Community should be dropped. 248 SOURCE DO RPF 249 Type: 0x0001 S = src AS # 250 F = 0x80 C = 0x00000000 251 H = Operator's defined T = none 252 L = 18 octets E = none 253 R = IANA assigned P = none 255 DESCRIPTION - All transit traffic which source addresses have been 256 tagged by such Wide BGP Community should be subject to Reverse Path 257 Forwarding check when crossing Autonomous System boundaries. Source 258 Autonomous System number specified in the body of this community 259 should directly indicate the peering interfaces on which such RPF 260 check should be performed. 262 HIGH PRIORITY PREFIX 263 Type: 0x0001 S = src AS # 264 F = 0x80 C = 0x00000000 265 H = 0x00 T = none 266 L = 18 octets E = none 267 R = IANA assigned P = none 269 DESCRIPTION - BGP prefixes carrying such Wide BGP Community should be 270 advertised to restarting peers before other prefixes received by 271 given BGP speaker. 273 ATTACK TARGET 274 Type: 0x0001 S = src AS # 275 F = 0x80 C = 0x00000000 276 H = Operator's defined T = none 277 L = 18 octets E = none 278 R = IANA assigned P = none 280 DESCRIPTION - The ATTACK_TARGET Registered Wide BGP Community 281 indicates that BGP prefixes carrying such community are receiving 282 unusual amount of unwanted traffic most likely due to some form of 283 network attack. Network devices capable of analyzing and mitigating 284 such attacks can use such community as a hint on what destinations to 285 focus the most. 287 2.2.2. Advertisement control Registered Wide BGP Communities 289 NO ADVERTISE TO AS 290 Type: 0x0001 S = src AS # 291 F = 0x80 C = 0x00000000 292 H = Operator's defined T = Type_1 (Peer_AS) 293 L = 25 octets E = none 294 R = IANA assigned P = none 296 DESCRIPTION - All routes received which carry such Wide BGP Community 297 containing this value MUST NOT be advertised to BGP peer which 298 Autonomous System number has been listed in the TARGET TLV field of 299 this community. 301 Semantically specifying the reserved Autonomous System value of 302 0xFFFFFFFF (ANY AS) would be an equivalent of using NO_ADVERTISE 303 Well-Known Standard BGP Community Attribute. 305 ADVERTISE TO AS 306 Type: 0x0001 S = src AS # 307 F = 0x80 C = 0x00000000 308 H = Operator's defined T = Type_1 (Peer_AS) 309 L = 25 octets E = none 310 R = IANA assigned P = none 312 DESCRIPTION - All routes received carrying such Wide BGP Community 313 containing this value MUST ONLY be advertised to BGP peers which 314 Autonomous System number is specified in the TARGET TLV field of this 315 community. 317 Semantically specifying the reserved Autonomous System value of 318 0xFFFFFFFF (ANY AS) would be an equivalent of advertisement to all 319 neighbors. Post execution this community MUST be removed. 321 ADVERTISE AND SET NO EXPORT 322 Type: 0x0001 S = src AS # 323 F = 0x80 C = 0x00000000 324 H = Operator's defined T = Type_1 (Peer_AS) 325 L = 25 octets E = none 326 R = IANA assigned P = none 328 DESCRIPTION - All routes received carrying such Wide BGP Community 329 containing this value MUST be advertised to BGP peer which Autonomous 330 System number is specified in the TARGET TLV field of this community 331 with NO_EXPORT Standard BGP Community attached. 333 Semantically specifying in TARGET TLV the reserved Autonomous System 334 value of 0xFFFFFFFF (ANY AS) would be an equivalent of advertisement 335 to all neighbors with NO_EXPORT community being set. Post execution 336 this community MUST be removed. 338 2.2.3. AS source marking Registered Wide BGP Communities 340 FROM PEER 341 Type: 0x0001 S = src AS # 342 F = 0x80 C = 0x00000000 343 H = 0x00 T = none 344 L = 18 octets E = none 345 R = IANA assigned P = none 347 DESCRIPTION - Autonomous System may attach this community to routes 348 received from their EBGP peers to later, when advertising them 349 outside the domain, apply or relax local policies only on such group 350 of destinations. 352 FROM CUSTOMER 353 Type: 0x0001 S = src AS # 354 F = 0x80 C = 0x00000000 355 H = 0x00 T = none 356 L = 18 octets E = none 357 R = IANA assigned P = none 359 DESCRIPTION - Autonomous System may attach this community to routes 360 received from their customers to later, when advertising them outside 361 the domain, apply or relax local policies only on such group of 362 destinations. 364 INTERNAL 365 Type: 0x0001 S = src AS # 366 F = 0x80 C = 0x00000000 367 H = 0x00 T = none 368 L = 18 octets E = none 369 R = IANA assigned P = none 371 DESCRIPTION - Autonomous System may attach this community to routes 372 originated in their own domain to later, when advertising them 373 outside the domain, apply or relax local policies only on such group 374 of destinations. 376 FROM UPSTREAM 377 Type: 0x0001 S = src AS # 378 F = 0x80 C = 0x00000000 379 H = 0x00 T = none 380 L = 18 octets E = none 381 R = IANA assigned P = none 383 DESCRIPTION - Autonomous System may attach this community to routes 384 received from their EBGP upstream peers to later, when advertising 385 them outside the domain, apply or relax local policies only on such 386 group of destinations. 388 FROM IX 389 Type: 0x0001 S = src AS # 390 F = 0x80 C = 0x00000000 391 H = 0x00 T = none 392 L = 18 octets E = none 393 R = IANA assigned P = none 395 DESCRIPTION - Autonomous System may attach this community to routes 396 received from their EBGP peering sessions with the Internet Exchange 397 peers or with Route Server to later, when advertising them outside 398 the domain, apply or relax local policies only on such group of 399 destinations. 401 LEARNED FROM AS 402 Type: 0x0001 S = src AS # 403 F = 0x80 C = 0x00000000 404 H = 0x00 T = Type_1 (Peer_AS) 405 L = 25 octets E = none 406 R = IANA assigned P = none 408 DESCRIPTION - Autonomous System may attach this community to routes 409 received from their EBGP peer by explicitly tagging them with their 410 peer's Autonomous System number as a value of the TARGET TLV field. 411 If the AS number is a two octet number first two octest will be 412 filled with zero. It is possible to use this to also carry private 413 AS number of customers. 415 2.2.4. Return path influencing Registered Wide BGP Communities 417 PATH HINT 418 Type: 0x0001 S = src AS # 419 F = 0x80 C = 0x00000000 420 H = Operator's defined T = Type_1 (AS#) 421 L = 25 octets E = none 422 R = IANA assigned P = none 424 DESCRIPTION - Autonomous System receiving such Wide BGP Community 425 value should prefer for BGP prefixes received with such community 426 (for example by increasing value of local preference on ingress), a 427 BGP path which traverses Autonomous System number which has been 428 specified in the TARGET TLV field of this community. Post execution 429 this community SHOULD be kept. 431 NEGATIVE PATH HINT 432 Type: 0x0001 S = src AS # 433 F = 0x80 C = 0x00000000 434 H = Operator's defined T = Type_1 (AS#) 435 L = 25 octets E = none 436 R = IANA assigned P = none 438 DESCRIPTION - Autonomous System receiving such Wide BGP Community 439 value should prefer for BGP prefixes received with such community 440 (for example by increasing value of local preference on ingress), a 441 BGP path which DOES NOT traverses Autonomous System number which has 442 been specified in the TARGET TLV field of this community. Post 443 execution this community SHOULD be kept. 445 2.2.5. AS_PATH modifying Registered Wide BGP Communities 447 PREPEND N TIMES BY AS 448 Type: 0x0001 S = src AS # 449 F = 0x80 C = 0x00000000 450 H = Operator's defined T = Type_1 (AS#) 451 L = 29 octets E = none 452 R = IANA assigned P = Type_4 (0xAA) 454 DESCRIPTION - The Autonomous System specified in the TARGET TLV field 455 of such community should prepend N times (encoded as 0xAA) its own 456 Autonomous System number when advertising routes tagged with this 457 community to peers. Number of requested AS prepends is provided in 458 the PARAMETERS TLV field value. Post execution this community MUST 459 be removed. 461 PREPEND N TIMES TO AS 462 Type: 0x0001 S = src AS # 463 F = 0x80 C = 0x00000000 464 H = Operator's defined T = Type_1 (AS#) 465 L = 29 octets E = none 466 R = IANA assigned P = Type_4 (0xAA) 468 DESCRIPTION - The Autonomous System advertising routes externally 469 should prepend N times (encoded as 0xAA) its own Autonomous System 470 number when advertising routes tagged with this community to peer 471 which AS number is defined by TARGET TLV field. Number of requested 472 AS prepends is provided in the PARAMETERS TLV field. Post execution 473 this community MUST be removed. 475 REPLACE BY 476 Type: 0x0001 S = src AS # 477 F = 0x80 C = 0x00000000 478 H = Operator's defined T = Type_1 (AS#) 479 L = 25 octets E = none 480 R = IANA assigned P = none 482 DESCRIPTION - All routes marked with such community advertised by an 483 Autonomous System to all of its external peers should have any 484 occurrence of an Autonomous System number specified in the TARGET TLV 485 field replaced with advertising domain's local Autonomous System 486 number. Post execution this community MUST be removed. 488 2.2.6. Local Preference Registered Community 490 LOCAL PREFERENCE 491 Type: 0x0001 S = src AS # 492 F = 0x80 C = 0x00000000 493 H = Operator's defined T = none 494 L = 22 octets E = none 495 R = IANA assigned P = Type_4 (ABBBBBBB) 497 SEMANTICS of PARAMETERS TLV 498 1 octet 1st bit indicates: 499 0-increment, 1-decrement 500 7 bits - value of local preference value 1..127 502 DESCRIPTION - Autonomous System may suggest to its EBGP neighbor the 503 following adjustments to the value of local preference as specified 504 by given domain's local policy. The values of requested increment or 505 decrement of local preference value is carried in the PARAMETERS TLV 506 field. Post execution this community MUST be removed. 508 2.2.7. AS_PATH TTL Registered Community 510 AS_PATH TTL MAX RADIUS 511 Type: 0x0001 S = src AS # 512 F = 0x80 C = 0x00000000 513 H = Operator's defined T = none 514 L = 22 octets E = none 515 R = IANA assigned P = Type_4 (0xAA) max AS_PATH radius 517 DESCRIPTION - Autonomous System may suggest to drop advertised prefix 518 by any transit network if its AS_PATH attribute length would be equal 519 or greater to encoded value both inbound or outbound of EBGP session. 520 The value of max AS_PATH length allowed is specified in the 521 PARAMETERS TLV field of the community. Post comparison this 522 community MUST be kept. 524 2.2.8. GEO-LOCATION Registered Community 526 GEOGRAPHIC LOCATION WHERE BGP ROUTE IS INTRODUCED TO AS 527 Type: 0x0001 S = src AS # 528 F = 0x80 C = 0x00000000 529 H = Operator's defined T = none 530 L = 26 octets E = none 531 R = IANA assigned P = Type_8 (5 UTF-8 characters) 533 DESCRIPTION - Autonomous Systems may attach this community to routes 534 received from EBGP neighbors or introduced to BGP by other routing 535 protocols to identify the geographic location where the route was 536 introduced to the AS. The "right-most" two octets of PARAMETERS TLV 537 correspond to an ISO3166-1 alpha-2 country identifier, while the 538 "left-most" three octets may express a more specific geographic 539 location, such as a city or IXP encoded in 3 octets. 541 Example: 543 Wide BGP Community describing route learnt by the AS at London, GB 544 HOP COUNT - operator defined 545 LENGTH - 26 546 PARAMETERS - 3 octets locality string + 2 octets country id. 548 0 1 2 3 549 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 550 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 551 | 0x0001 | 0x80 | 0xFF | 552 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 553 | 0x001A | 554 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 555 | IANA assigned | 556 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 557 | 0x000000AS | 558 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 559 | 0x00000000 | 560 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 561 | 0x08 | 0x0008 | 562 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 563 | "L" | "O" | "N" | "G" | 564 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 565 | "B" | 566 +-+-+-+-+-+-+-+-+ 568 3. Example 570 Customer of the source AS number 100 requests to execute AS_PATH 571 prepend 4 times when advertising the prefixes to AS number 2424. We 572 will use the following community assigned on ingress or at the prefix 573 origination. 575 PREPEND N TIMES TO AS 576 Type: 0x0001 S = 0x00000064 (dec 100) 577 F = 0x80 C = 0x00000000 578 H = 0x00 T = 0x00000978 (dec 2424) 579 L = 0x001D (dec 29 octets) E = none 580 R = IANA assigned P = 0x04 (dec 4) 582 0 1 2 3 583 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 584 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 585 | 0x0001 | 0x80 | 0x00 | 586 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 587 | 0x001D | 588 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 589 | IANA assigned | 590 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 591 | 0x00000064 | 592 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 593 | 0x00000000 | 594 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 595 | 0x01 | 0x0007 | 596 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 597 | 0x00000978 | 598 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 599 | 0x04 | 0x0004 | 600 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 601 | 0x04 | 602 +-+-+-+-+-+-+-+-+ 604 4. ECMP Hint Registered Community 606 AS_PATH TTL MAX RADIUS 607 Type: 0x0001 S = src AS # 608 F = 0x80 C = publisher AS # 609 H = Operator's defined T = none 610 L = 22 octets E = none 611 R = IANA assigned P = Type_4 (0xAA) max AS_PATH radius 613 DESCRIPTION - In multistage networks with large scale Equal Cost 614 MultiPath (ECMP), it is often useful to separate flows towards a 615 single destination among different paths along the parallel set at 616 each stage. This wide community allows the operator to send a "hint" 617 to the ingress router on how to set either the MPLS entropy label 618 [RFC6790] or the IPv6 flow label [RFC3697] to achieve such flow 619 separation. The Integer list given in the community can contain a 620 label that is used by the receiver: Directly as an IPv6 flow label, 621 Directly as an MPLS entropy label, As a seed used to calculate either 622 a flow or entropy label 624 5. Security considerations 626 All the security considerations for BGP Communities as well as for 627 BGP Extended Communities RFCs apply here. 629 6. IANA Considerations 631 This document requests IANA to define and maintain a new registry 632 named: "Registered Wide BGP Communities Values". The reserved pool 633 of 0x00000000-0xFFFFFFFF has been defined for its allocations. The 634 allocation policy is on a first come first served basis. 636 This document makes the following assignments for the Registered Wide 637 BGP Community values: 639 +---------------------------------+------------+ 640 | Name | Type Value | 641 +---------------------------------+------------+ 642 | BLACKHOLE | 1 | 643 | SOURCE FILTER | 2 | 644 | SOURCE DO RPF | 3 | 645 | HIGH PRIORITY PREFIX | 4 | 646 | ATTACK TARGET | 5 | 647 | | | 648 | NO ADVERTISE TO AS | 6 | 649 | ADVERTISE TO AS | 7 | 650 | ADVERTISE AND SET NO EXPORT | 8 | 651 | | | 652 | FROM PEER | 9 | 653 | FROM CUSTOMER | 10 | 654 | INTERNAL | 11 | 655 | FROM UPSTREAM | 12 | 656 | FROM IX | 13 | 657 | LEARNED FROM AS | 14 | 658 | | | 659 | PATH HINT | 15 | 660 | PATH NEGATIVE HINT | 16 | 661 | | | 662 | PREPEND N TIMES BY AS | 17 | 663 | PREPEND N TIMES TO AS | 18 | 664 | REPLACE BY | 19 | 665 | | | 666 | LOCAL PREFERENCE | 20 | 667 | AS_PATH TTL MAX RADIUS | 21 | 668 | GEO-LOCATION | 22 | 669 | ECMP HINT | 23 | 670 | | | 671 | FREE POOL | 24.. | 672 +---------------------------------+------------+ 674 7. Contributors 676 The following people contributed significantly to the content of the 677 document: 679 Bruno Decraene 680 France Telecom 681 38-40 rue du General Leclerc 682 92794 Issi Moulineaux cedex 9 683 France 684 Email: bruno.decraene@orange-ftgroup.com 686 Shintaro Kojima 687 OTEMACHI 1st. SQUARE EAST TOWER, 3F 688 1-5-1, Otemachi, 689 Chiyoda-ku, Tokyo 100-0004 690 Japan 691 Email: koji@mfeed.ad.jp 693 Juan Alcaide 694 Cisco Systems 695 Research Triangle Park, NC 696 United States 697 Email: jalcaide@cisco.com 699 Burjiz Pithawala 700 Cisco Systems 701 170 West Tasman Dr 702 San Jose, CA 703 United States 704 Email: bpithaw@cisco.com 706 Saku Ytti 707 TDC Oy 708 Mechelininkatu 1a 709 00094 TDC 710 Finland 711 Email: ytti@tdc.net 713 Paul Jakma 714 School of Computing Science, Uni. of Glasgow 715 Sir Alwyn Williams Building 716 University of Glasgow 717 Glasgow 718 G1 5AE 719 UK 720 Email: paulj@dcs.gla.ac.uk 721 Russ White 722 Ericsson 723 Oak Island, NC 28465 724 USA 725 Email: russw@riw.us 727 8. Acknowledgments 729 Authors would like to thank Enke Chen, Pedro Marques, Alton Lo and 730 Jeff Wheeler for their valuable input. 732 9. References 734 9.1. Normative References 736 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 737 Requirement Levels", BCP 14, RFC 2119, March 1997. 739 [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway 740 Protocol 4 (BGP-4)", RFC 4271, January 2006. 742 [RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended 743 Communities Attribute", RFC 4360, February 2006. 745 9.2. Informative References 747 [RFC1997] Chandrasekeran, R., Traina, P., and T. Li, "BGP 748 Communities Attribute", RFC 1997, August 1996. 750 [RFC1998] Chen, E. and T. Bates, "An Application of the BGP 751 Community Attribute in Multi-home Routing", RFC 1998, 752 August 1996. 754 [RFC4384] Meyer, D., "BGP Communities for Data Collection", BCP 114, 755 RFC 4384, February 2006. 757 [RFC4893] Vohra, Q. and E. Chen, "BGP Support for Four-octet AS 758 Number Space", RFC 4893, May 2007. 760 [RFC5668] Rekhter, Y., Sangli, S., and D. Tappan, "4-Octet AS 761 Specific BGP Extended Community", RFC 5668, October 2009. 763 Authors' Addresses 764 Robert Raszuk (editor) 765 Mirantis Inc. 766 615 National Ave. #100 767 Mt View, CA 94043 768 USA 770 Email: robert@raszuk.net 772 Jeffrey Haas 773 Juniper Networks 774 1194 N.Mathilda Ave 775 Sunnyvale, CA 94089 776 US 778 Email: jhaas@pfrc.org